Let Δ=a2(a+λ)2(a−λ)2b2(b+λ)2(b−λ)2c2(c+λ)2(c−λ)2 Apply R2→R2−R3Δ=a2(a+λ)2−(a−λ)2(a−λ)2b2(b+λ)2−(b−λ)2(b−λ)2c2(c+λ)2−(c−λ)2(c−λ)2=a24aλ(a−λ)2b24bλ(b−λ)2c24cλ(c−λ)2(∵(x+y)2−(x−y)2=4xy) Taking out 4 common from R2 =4a2aλa2+λ2−2aλb2bλb2+λ2−2bλc2cλc2+λ2−2cλ Apply R3→[R3−(R1−2R2)]=4a2aλλ2b2bλλ2c2cλλ2 Taking out λ common from R2 and λ2 from R3. =4λ(λ2)a2a1b2b1c2c1 =kλa2a1b2b1c2c1⇒k=4λ2